Method and device for applying a sealing compound to a surface

Abstract

A device for applying a sealing compound into a closure cap for containers comprising: an outer stamp ( 18 ) and a concentric inner stamp ( 14 ), the stamps being movable with respect to each other, an annular gap ( 26 ) between the stamps ( 14, 18 ), which is open towards the outside or the inside and of which at least one section is variable between an initial gap width and a gap width zero in the movement direction of the stamps in an axial relative movement of the stamps ( 14, 18 ), a feeding system for plasticized sealing compound within a stamp, which is connected to the annular gap ( 26 ), a mechanism that prevent any reflux of the melt from the annular gap, and adjustment mechanism for at least one of the stamps for changing the gap width of the annular gap.

The invention claimed is: 
     
       1. A method for applying a sealing compound to a surface, wherein a ring-shaped structure is formed from a plasticized sealing compound and subsequently deposited on the surface, wherein:
 the plasticized sealing compound is annularly brought into a temperature-controlled annular gap having a variable gap width, said annular gap being disposed between an inner stamp and an outer stamp, said inner stamp having a lower flange and said outer stamp having a lower surface, said lower surface being constructed and arranged to mate with said lower flange, 
 the sealing compound is completely squeezed out of the annular gap by fast reduction of the annular gap width to zero, and is formed to the ring-shaped structure and laid down on the surface thereafter, 
 wherein the annular gap width is reduced with such a great velocity and the sealing compound is squeezed out with such a high velocity that any adherence of the melt on gap edges, as well as on surfaces neighboring to the annular gap, is avoided. 
 
     
     
       2. The method according to  claim 1 , wherein the ring-shaped structure is deposited on the surface immediately when it arises from the annular gap. 
     
     
       3. The method of  claim 1 , wherein the ring-shaped structure is subsequently pressed against the surface by a ring-shaped pressing tool, the tool is at room temperature or less, and formed to a planar sealing ring to provide a sealing surface. 
     
     
       4. A method of  claim 1 , wherein the plasticized sealing compound is radially squeezed out of the annual gap towards the outside of the annular gap. 
     
     
       5. The method of  claim 4 , wherein the plasticized sealing compound is squeezed out of the annular gap obliquely downwards from the annular gap. 
     
     
       6. A method of  claim 1 , wherein the plasticized sealing compound is radially squeezed out of the annual gap towards the inside of the annular gap. 
     
     
       7. A method of  claim 6 , wherein the plasticized sealing compound is squeezed out of the annual gap obliquely downwards from the annular gap. 
     
     
       8. The method of  claim 1  wherein the ring-shaped structure is incorporated into a closure cap for containers. 
     
     
       9. The method of  claim 1  wherein the emergence end of the annular gap is positioned with respect to the surface such that the ring-shaped structure contacts the surface as soon as it has been squeezed out of the annular gap, and a film possibly still existing between the closed annular gap and the ring-shaped structure is broken by subsequently lowering the surface. 
     
     
       10. The method of  claim 1  wherein the ring-shaped structure is deposited on the inner side of a bottom of a twist-off cap and is subsequently pressed against a deepening by a pressing tool, wherein one single ring-shaped pressing stamp is used as the pressing tool and the volume of the ring-shaped structure relative to the volume of the deepening is dimensioned such that in the pressing process, the sealing compound is bead-like deformed beyond an edge of the deepening at least towards the outer side of the deepening.